Preparation and Characterization of Microencapsulated Phase Change Materials for Use in Building Applications

Phase change materials (PCMs) are increasingly studied for thermal energy storage in building applications. These materials can absorb and release thermal energy during phase transitions, making them useful for regulating indoor temperatures. However, PCMs are often sensitive to environmental conditions and require encapsulation to maintain stability and performance. While commercial microencapsulated PCMs are available, their properties and emissions characteristics are not always fully characterized. This gap motivated the development of a new laboratory-prepared microencapsulated PCM and a direct comparison with a commercial product. Prior research has shown that paraffin wax is a suitable PCM for building applications due to its melting point range. Yet, no prior work had resolved the comparative mechanical and thermal properties of lab-made versus commercial microcapsules in detail.

The aim of this study was to prepare and characterize a laboratory-made microencapsulated phase change material (MPCM) and compare it to a commercially available MPCM. The specific problem addressed was the lack of detailed comparative data on mechanical, thermal, and VOC emission properties of lab-made versus commercial microcapsules. The motivation stemmed from the need to understand how these materials perform in real-world building applications. The study sought to evaluate thermal energy storage capacity, mechanical resilience, and VOC emissions under controlled heating conditions. By comparing the lab-made sample (M-2) with the commercial sample (Micronal® DS 5008 X), the researchers aimed to identify any advantages or limitations of the laboratory-prepared material. This work contributes to the broader field of PCM development by providing a direct empirical comparison of two microcapsulated materials.

The study employed a combination of analytical techniques to evaluate the properties of the microencapsulated phase change materials. Scanning electron microscopy (SEM) was used to assess the morphology and size distribution of the microcapsules. Differential scanning calorimetry (DSC) measured the thermal energy storage capacity of the materials. Nano-indentation was applied to determine mechanical properties such as elastic modulus and load-displacement behavior. Gas chromatography/mass spectrometry (GC-MS) was used to analyze volatile organic compound (VOC) emissions at elevated temperatures. The MPCM samples were prepared using paraffin wax as the phase change material and an acrylic shell for encapsulation. Both the laboratory-made sample (M-2) and the commercial sample (Micronal® DS 5008 X) were subjected to identical characterization protocols to ensure a fair comparison. The results were analyzed to determine differences in thermal performance, mechanical strength, and VOC emissions.

The thermal energy storage (TES) capacities of the M-2 and Micronal® DS 5008 X samples were measured at 111.73 J·g⁻¹ and 99.3 J·g⁻¹, respectively. Both samples exhibited a melting temperature of approximately 21 °C, making them suitable for building applications. SEM analysis revealed that both microcapsules had an average size of 6 μm and a spherical shape. Nano-indentation testing showed that M-2 had slightly better mechanical properties, including higher elastic modulus and load-displacement characteristics. GC-MS analysis at 65 °C detected VOC emissions from both samples after 10 minutes of heating. However, the VOC peaks from M-2 were less intense than those from the commercial sample, indicating lower VOC emissions. The spherical morphology and size consistency of both materials suggest good suitability for integration into building materials. These findings suggest that M-2 may offer advantages in mechanical and environmental performance over the commercial product.

The authors concluded that the laboratory-made MPCM (M-2) demonstrated comparable or superior performance to the commercial Micronal® DS 5008 X sample in several key areas. The thermal energy storage capacity of M-2 was higher, and its mechanical properties, as measured by nano-indentation, were slightly better. Additionally, M-2 showed lower VOC emissions under controlled heating conditions, which is an important consideration for building applications. These findings suggest that M-2 could be a viable alternative to commercial microencapsulated PCMs for use in buildings. The spherical morphology and consistent size of both samples support their potential for integration into construction materials. The authors propose that these results may inform future material development and application strategies for PCM-based thermal regulation systems. No prior work had resolved the comparative VOC emissions of lab-made and commercial microcapsules, making this study a novel contribution to the field.